As the people's concern over health is increasing, there is worry about the influence of trans fatty acids on health (Alice, H. Lichtenstein, et al., EFFECT OF DIFFERENT FORMS OF DIETARY HYDROGENATED FATS ON SERUM LIPOPROTEIN CHOLESTEROL LEVELS, “The New England Journal of Medicine”, USA, the Massachusetts Medical Society, 1999, Vol. 340, No. 25, pp. 1933-1940), and there is a tendency to refrain from its ingestion.
On one hand, it has been revealed that diacylglycerol has a function of suppressing the accumulation of body fat (JP-A 4-300826). For ingestion of an effective amount of diacylglycerol in a wide variety of daily consumed fat and oil processed products and in various foods containing them, fat and oil processed food containing diacyl glycerol at a high concentration should be consumed. A fat and oil composition containing diacylglycerol in oil is proposed in, for example, JP-A 63-301765. An invention described in JP-A 63-301765 includes adding a wide variety of partially hydrogenated oils as solid fat to diacylglycerol having a melting point of less than 20° C. which is liquid at ordinary temperature, to give a highly foaming fat and oil composition. However, diacylglycerol is a liquid, and thus commercial products such as butter cream, etc. requiring shape retention at an ordinary temperature should be blended with a large amount of partially hydrogenated oils, and cannot be blended with a large amount of diacylglycerol enough to exhibit its health function sufficiently. The partially hydrogenated oils contain a large amount of trans-unsaturated fatty acid, so its influence on life style-related diseases is concerning, but when the trans-unsaturated fatty acid is reduced, there is a problem that shortening, margarine, etc. hardly attain satisfactory foaming properties and shape retention.
As fat and oil compositions containing diacylglycerol and triacylglycerol, various combinations are proposed not only in JP-A 63-301765 supra but also in JP-A 61-63242, WO-A 95/22256, WO-A 95/22257, WO-A 96/32022 or WO-A 99/48378, JP-A 2001-61411, JP-A 63-301743, JP-A 10-176181 and JP-A 2001-64671.